Frozen pipe story

Dan_15

This morning I awoke to no hot water. I knew it could not have been my new Buderus, because, well, its NEW. I went down to the cellar to investigate and I realized right away that something was amiss because it was cold enought that I could see my breath. To my great shame, I realized that I had inadvertently left the garage door open all night and subfreezing air was blowing through my cellar door directly onto my new boiler. So I closed the garage door and checked out the system. The boiler was working fine, pipes were all hot, and it was making plently of hot water for the heat zone. But the DHW zone was not calling for heat. Why not? The DHW water supply pipe was hot, and so was the boiler feed pipe to the indirect tank. I felt the boiler return from the indirect and it was lukewarm. Then I felt the cold water feed pipe and it also seemed fine until it reached the flow check and tee to the boiler. After the flow check and tee, the piping down to the indirect cold feed was progressively colder, and was icy cold at the bottom near the 90 elbow at the floor. I surmised that the cold air blowing into the cellar all night must have frozen the indirect feed pipe near the floor where it was coldest, which was causing a vacuum so that the hot water could not leave the tank. Sure enough my diagnosis was confirmed when I opened them cold feed drain valve near the floow and nothing came out. Not running any hot water all night allowed the standing water to freeze. So, how to unfreeze the pipe? Feeling pretty stupid at creating the problem, I did not want to cause the pipe to burst by pouring hot water on it. So I placed a space heater a few inches from the frozen area near the floow, and five minutes later I hear the ice break free. Hot water was back, and I saved my oil company the trouble of coming out for a stupid service call. Its a story with a good ending, but is this the correct way to unfreeze a pipe? Thanks for listening.

Weezbo

Many people have had the similar experience...

and when things go a bit more south,quite often they need it repaired in a hurry right NOW! so we load the truck up with heaters of every sort and description and dash over and Pump Btus into the place BIG TIME...while the set up of all the heaters etc is going on some one else goes and pulls cover plates off the convectors,and another guy runs about and moves stuff away from the walls,and another guy checks the corners and opens every door in the place and another guy checks the boiler....so when i show up with my superman cape on it is time to roll...:) this only happens when you can get a crew of guys with at least two marbles in thier pocket. on the phone i direct the ho to find his wifes hair drier and aim it at corners and cold spots for a few mins,turn up the stove throw some wood in the barrel stove ...get heat of some sort happening..You were lucky... ice in the lines can destroy recirc pumps just as easily as a chunk of solder...so if you hear a growling sound in the domestic recirc...likely the "Hawk" got it.

S Milne

burst piping

"Feeling pretty stupid at creating the problem, I did not want to cause the pipe to burst by pouring hot water on it"

Where would you get that idea ?

Whether you poured hot water on it or heat it with some other source, you would not have damaged the pipe.

The burst pipe is caused by the ice freezing, sometimes from expansion of the ice , but more often the hydrolic preasure created by ice forming on two spots and pushing towards a center spot. Notice its usally a elbow that blows ? Thats because the water has frozen in each leg of the pipe and forced itself towards the ell. The hydrolic preasure it creates is more than the ell can take.

Scott

hr

To determine if a pipe is frozen..

We use to do a lot of pipe thawing in the mountains of Utah. In the years that we had little or light snowfall the meter pits in the yard were the most common place to find freeze ups.

It was also common when the city snow removal loaders worked a street pushing back the snowbanks to allow the plows "working room". If the meter pit had a foot of snow over it they would be freeze proofed. Strip the snow, and often some of the lawn and the phone would start ringing.

Remove the meter pit lid, sprinkle a handful of snow on the meter yoke. If it melts, it's not frozen. If it sits on the pipe, white and pretty, 90% of the time it's frozen. Try it!

hot rod

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Dan_15

Im not a pro

OK, well Im just a homeowner looking to learn something. I guess I assumed that the general proposition--that shocking something cold with something hot would cause severe fluctuation in the material and cause it to weaken or break--applies to copper pipes.

JimGPE_16

I've always heard...

The first thing you want to do is shut off the water supply. That way, when you melt the ice plug if you have split a pipe or worked a joint lose, you're only going to have the water in the pipe to deal with, not the entire contents of the local resouvoir.

S Milne

Not at all Dan

I thaw frozen pipes with a torch. We use thawing machines, much like a welding machine. I have thawed frozen pipes by holding it in my hand. You can not "shock" a pipe into splitting.

The busting happens because of the ice and the hydrolic preasure it puts on the tubing and fittings. Water expands seven times its size when frozen. Thats ALOT of preasure in a closed pipe.

I can "look" at a pipe and tell by the frost on it weather or not it is frozen.

I can feel a pipe and tell which spot the freeze plug is.

I have done freeze ups for YEARS.

I was an apprentice for four months when we had the deepest freeze we had experienced in years. They gave me a torch and some slip couplings and a list of customers and said " Call us when your done". AS a Master Plumber for twenty years I've seen ALOT of freeze ups.

Scott

jeff_51

leave water on

its actually the pressure of the water that will break the ice plug free. We use an electric pipe thawing machine like a Hot Shot which passe an electic current through the pipe and will melt just the ice touching the pipe which allows water to begin to flow and it is the flowing water that actually will melt the ice in the line. Only takes a few seconds once the water starts to flow which only happens if you have the water on and a faucet open. If you have a split pipe, that of course is a differant matter. Any heat source on that pipe should be ok, just leave the pressure on and a faucet open( again. uless it is split}

Weezbo

What Scott describes is Chasing the water...

you take a torch and chase the water along the pipein order for it to flow very little water needs to flow thru the pipe....the moving water does the rest ...the other trick is reliving the pressure at the valves if They Arent frozen, throwing large hand fuls of salt in the toilet tanks and bowls and traps is another swift trick that works while you are buzy doing other things...in 100 mile an hour winds in 60 below you can go outside with boiling water and pour it right on the black iron fuel pipe and Voila instant oil supply

Ted Robinson

Thawing frozen pipes

Quite a few years ago I attended college in far, Northern NY State. Once in a while when it was cold without much snow cover you would see the village public works truck connect a welding generator between the nearest fire hydrant, and the house service pipe. I suppose that with enough amps they melted whatever ice there was.

hr

Jim

I would suggest one never start to thaw a pipe UNTIL you know where the shutoff valve is, and that it does in fact work.

I agree pipes GENERALLY split when they freeze, but I have had them split while thawing, also. Usually copper.

The water pressure sure does speed up the thawing but can make a huge, cold mess if it gets away from you

hot rod

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S Milne

Hot Rod

Explain to me how they can split "while" thawing ?

I have been doing this for years and have never experienced that.

I also read alot about freezing and don't see the physics behind that. I am alway willing to learn more.

The majoity of spits in copper has been documented to come from the hydrolic preasure that builds up between two freeze plugs pushing towards each other. Many times that is a elbow. Thast why alot of time when you find a frozen pipe there will be a small amount of water there, even though the water is frozen in the pipe. Thats because the preasure built up and blew out the pipe and Then froze.

BY the way, ever be in a house when the cast iron radiator lets go ? THATS preasure.

Scott

hr

Scott, allow me to BS my way

out of this :0

A section of 1/2" type L copper tube freezes with 60 psi pressure at time of freeze up. The phase change to ice and related expansion causes internal pressure to rise to, let's say, 7764.5 psi inside the frozen section of pipe. No visable splits are seen.

Joe plumber comes along and picks a spot mid pipe and pours the fire to 'er. The ice changes phase, again, to water below his torches tip, the plumber nods off in the dim glow and comforting screech of the turbo torch.

The water boils, changes phase again, to steam! In that short section below the torch.

The pressure rises in that section to 7766 psi, which we all know is "actual burst pressure" for 5/8" anneled copper (at room temperature)

The tube can't just can't handle pressure, as Billy Joel would sing

The tube splits, showers and wakes the sleeping plumber. He scurries out never knowing what hit him.

How'd I do?

I agree with you MOST often the 7765 psi is exceeded during the freezing phase change. But it is possible the addition of steam, and the related pressure increase, in the ice locked section, could in fact cause a pipe to split.

Don't make me go out in the subfreezing weather here with some copper tube, torch, and hydraulic gauges

hot rod

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S Milne

I knew you where

going to go with the steam .....

Problem is I usually will heat pipes to the steaming point ( I can here the swoomp as it flash's ) as I try to get it to melt somewhere in the wall that I can't get to. A run on sentence to say naaahh, I don't think so.

I am ussually way over my head in conversations on the wall, but this is one that I feel I have some field experience.

I remember sitting with the welder with his little stub of cigar waiting for the main to thaw. Not mainy welders will take that one anymore. To much liabilty.

Once climbed into a crawl spave were there was so much insulation I did'nt dare light the torch. Held the pipe in my hand untill I heard the HO say " I got water".

Like I said you hav'nt lived untill you heard the cast iron radiators going off like shotguns from the ice. " No sir I think I'll stay here in the basement for a while ".

Don't mean to sound agresive HR. I am sure you seen your share

Scott

Weezbo

lets not bicker over minor technicalities *~/:)

lets just break all the unions and make sure we have water

Carl PE_2

heh.

You reminded me of a good one I'd just about forgotten.

Strip mall here in town. "Anchor store" on the end moved out. Custodian decided he was going to turn the heat off in that space.

Somehow, he failed to notice the 8" RPZ and all the meters in the stockroom. This was the store nearest the road, and therefore the water main.

Anyway, in the morning, nobody's got water. Custodian is in there with a salamander trying to thaw the place out.

At this point, I should probably mention that the RPZ is frozen solid and cracked. There's a 3/4" gap at the flange.

On the CITY side of the valve.

There is a salamander pointed directly at this ice cube. It is just starting to drip.

hr

We've all seen pictures

of water heaters that have exploded and gone through the roof. Usually caused by flashing to steam with a plugged safety, not freezing

Pipes or tanks don't really care what the source of the pressure that causes them to rupture. Exceed the burst strength of a material under pressure and....

I've seen, and caused , plenty of ball valves to pop out their o-ring seals by overheating them with the ball full of water and in the closed position, as I'm sure you have.

So why don't you think this is possible in a long section of frozen pipe?

hot rod

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Mark Eatherton1

Been there, seen that, don't want to see it again...

WAYYYYyyy badck when, I was a young apprentice working for my father, we got the frantic call from a newly opened Burger King. Frozen broken water lines EVERYWHERE.

Seems the company plumber was a traveling company from Florida (Imagine that) and were nowhere to be found when it came to do the repairs, so we charged in. Upon further inspection, I found that the fire protection lines were frozen and broken as well. Not being properly trained or licensed to work on FPS, we referred them to a small local company we were familiar with. They showed up, opened the outside mechanical closet serving the FPS riser and found that the whole riser was frozen solid. Gate valves popped out like frog eyes, laying on the floor and so on. He asked me if the water was off, to which I proclaimed "YEAH!" The store manager had told me that they had to call the city out to shut off the water, so I assumed everything was off. He placed a radiant propane space heater in the closet and took off for the warehouse to get the new valves and stuff he needed to rebuild the tree. I stayed in at attic, soldering Sioux Chief repair couplings like there was no tomorrow. About 30 minutes later I hear this gawd awful ROARRRRrrrr, and pretty soon, theres water coming from every sprinkler break in the attic. I yell at the top of my lungs to SHUT IT DOWN, to no avail. I'm getting soaked, and so is the whole attic. THe store manager pops his head up into the attic space and says "You better come down here in a hurry, we've got a real problem on our hands!!"

I scurry over, climb down the ladder and find the whole kitchen under 3" of water coming through the back door. I open the back door and see a wall of water coming from the fire protection closet. Seems they HADN'T shut off the fire protection system, only the potable system. I call the Denver Water Department and ask for an emergency shut down. They send a guy out, who's new to the job, and he's taking his sweet time to find the stop box. In the mean time, microwave ovens, case boxes of paper goods and everything else is floating out of this closet with the 4" uncapped fire protection main in it, and the water is flowing right around the corner, and into the back door of the restaurant. The floor drains can't keep up with the flow, and it's headed for the dining room. This is all happening between the 11:00 AM and Noon rush. Customers are looking at the employees waddling through the water, explaining to them that they don't have any soft drinks available. Care for a milk with that double whopper?

THe city finally contains the fire protection line just about the time its starting to burn its way through the triple layer of sheet roc in its ceiling, and things get a little more under control. About 1:30. I finally get the last potable break repaired, turn on the water, and hear someone saying "I'm with the City Health department, and I understand you're running this restaurant without water?" To which I reply, "Oh no sir, we've had some spot outages, but it's on, see??" To which he replied, "It's a damned good thing it IS on, or I'd be shutting you down and locking the doors..." He had a lock and chain in his hand.

Lesson learned, NEVER trust the word of another when it comes to making sure the water is off before you start doing repairs... Verify, or do it your self.

ME

Mad Dog

Dude! you fixed it

and thats that - good for you. Mad Dog

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ScottMP

Possible

not probable.

I am going to take a shot at this and say that a water heater blows not because of flashing to steam but from the excessive build up of steam. Dan mentions this in the LAOST. The older steam ships used to have this problem. I have stood next to boilers that were flashing and still lived to talk about it.

When heating a copper pipe with a torch, flashing do'es happen, as I said I do it on purpose, but I don't think ( big guess here ) it builds up enough steam preasure to blow a copper line out.

Thinking more on this, if a joint has been weakened from freezing or the soldered joint has been broken , again due to freezing, then it's possible for the joint to blow apart while you are thawing.

How'd I do .

Am I positive ? Not on this forum. I've been here long enough to know there is always someone smarter than me here. Matter of fact I am supprised we have not heard from a PHD. Constantine ?

Scott

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Constantin

Someone calling my name?

Hey Scott, are you telling me it's time to go back to school? I only have three degrees to date and thought the last one was going to kill me... Anyway, I know little to nothing about this subject. But that has never stopped me before! :-)

The variable I'll throw in is that when you're heating copper pipe, you're heating an excellent heat conductor. Unless the pipe is very long and/or you're only heating a very small area, I'd like to think that a lot of the heat energy will travel quite far via the copper and heat very long stretches of that excellent HX fluid called water before you can manage to get something to flash to steam inside the pipe.

But you've done that already, so never mind!

Even a tiny unfrozen conduit should allow most of the pressure to go by the wayside, the incompressibility of water being what it is. Naturally, if you're using a huge torch, you won't allow the water in the farther stretches to unfreeze before the area directly under the torch flashes to steam.

From a fluid dynamics standpoint, I imagine that the sudden change of direction will actually make bends the trouble spot in most instances when it comes to unfreezing long pipes. As the water in the center expands as it warms, the ice in the bend gets crushed increasingly into the 90° ellbow, filling all voids and making a very effective plug.

Thus, not having any experience and having thought about the subject for all of 30 seconds, I'd start at the bends and work my way in towards the middle of a pipe, with a small torch and a lot of patience. How did I do?

zeke

Here's another one. You come on the scene of frozen section.
Water between the ice plugs is 32 deg. Put the torch to the middle and locally heat the water; temp rises causing expansion. Water is virtually incompressible so the pressure shoots up and splits the pipe.

ScottMP

Zeke

No the pipe is allready split, I won't budge from that

Constantine .... I was only kidding.

Scott

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Constantin

Tease!

:-)

JohnWood1

Expansion rate of ice at different temps

HR;

In defense of your split while thawing......... Ice actually is at its' largest expansion at around 30F and starts shrinking as the temps get colder.....

Use as you wish

hr

Bottom line..

if Scott hasn't seen it is not possible

Tongue in cheek, of course.

hot rod

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S Milne

I am

The freeze up KING.

I'd put my tongue in my cheek but it would probable freeze there .

So John are you saying as it freeze's it gets bigger

Scott

Constantin

If you think about it for a second...

... that bizarre property of water to expand as it freezes is what enables fishes and other aquatic live to survive the winter. If the ice didn't float on top of water but froze and sank to the bottom like most metals, gases, etc. you'd have fishsticks instead of fish down there.

m dewolfe

frozen pipes

Read this story. This guy was thawing pipes with a torch in the basement when the neighbor spoted flames shooting out of the wall....gotta be careful with fire in a 100 year old house... http://news.newstimes.com/story.php?id=68488